Refrigerating apparatus



mac. 4, 1934. R M HVID 1,982,668

REFRIGERATING APPARATUS Original Filed Feb. 27, 1931 Patented n... 4,1934 UNITED STATES 1,982,668 REFRIGEBATING APPARATUS Basmus M. Hvld,Chicago, assimito Frigidaire Corporation, Dayton, Ohio, a corporation ofDelaware Application Rffibfllnry 27, 1931, Serial No.

owed November 1, 1933 My invention relates to mechanical refrigerationand particularly to a novel arrangement and apparatus similar to thatdisclosed in mycopending applications, Serial No. 499,753 filed De- 5cember 3, 1930 and Serial No. 513,374,1iled February 4, 1931.

The development of refrigerating apparatus has resulted in a degree ofperfection in which little or no mechanical trouble may reasonably beexpected over a period of years. This, however, does not include theprovisions for making and breaking contact of the motor circuit by theautomatic regulating apparatus. During normal operation, the motoroperating circuit is made and broken a multitude of times, and,- in thecourse of time, the contact points become oxidized or are likely tofuse, resulting in misopera-' tion. Furthermore, the cost of the switchmechanism is considerable.

I have, therefore, conceived it not only possible but desirable toemploy a constantly running motor-compressor. Such .a motor-compressoris thoroughly practical, and, when suitable provision is made forlubrication, will run indefinitely.

2 However, in order to insure efllcient refrigerating action some meansare necessary for controlling the compressor output, not only in orderto maintain a fairly constant temperature, but to reduce currentconsumption. This I accomplish by providing a thermostaticallycontrolled by-pass valve so arranged that when the temperature adjacentthe evaporator reaches a predetermined point, the valve will operate torelieve the compressor of load; in other words, to directly connect theinlet and outlet of the compressor.

Furthermore, this is accomplished in such a manner that a portion of thecondenser is utilized for a certain degree of cooling of the shortcircuited gas. In the arrangement shown, the result is accomplishedwithout measurably lowering the pressure in the high side and withoutinterference with the pressure or temperature conditions in theevaporator.

The invention will be more readily understood an ordinary box 10 havingan opening in arear wall thereof. Within the opening the refrigeratingunit is mounted for convenient insertion or by reference to theaccompanying drawing, in

, 11 Claims. (01. 62-115) removal. The unit comprises an evaporator 11of common form, containing a float 12 controlling an inlet valve 13, forcondensed liquid. An outlet pipe 14, for gas leads to the intake of thecompressor. The motor-compressor unit, indicated w generally by thenumeral 15, is of the form illustrated in detail in my co-pendingapplication, Serial N 0. 499,753 heretofore identified. This unitcontains a constantly running motor and a compressor within the limitsof the armature of the motor. The intake pipe 14 for the compressorcontains a check valve 16, the function of which will be hereafterdescribed, the pipe' being formed in a coil as at 17, to provide aresilient support for the motor compressor unit. The outlet pipe fromthe compressor is also formed in a coil as at 18 at the top of the unit,the pipe leading to the inner coil 19 of the condenser. The outer coilof the condenser terminates in the pipe 20 which extends directly to theinlet valve 13 of the evaporator.

The motor-compressor and other parts hereafter described, are containedwithin a doublewalled shell, the outer and inner walls 21, 22 beingseparated by suitable insulation 23 or by so providing a vacuum. Theshell is open at its backside in order that the heat generated by themotor may be dissipated by the circulation of air through the open side.The top and bottom walls of the inner shell 22 are somewhat in- 35clined outwardly in order to facilitate circulation. The evaporator issupported on the outer shell by the lugs 24. The condenser is located ina vertical plane alongside of the wall of the box, and when the box islocated adjacent to a building wall 25, a strong upward movement of airwill efficiently cool the coils.

The by-pass valve, best shown in Fig. 2, is of simple construction, verysmall in size and is arranged alongside of the motor compressor 15within the cavity of the shell. The mechanism includes a head 26containing a valve seat 27 and pipe connections 28, 29. The pipe 28extends upwardly and connects with one of the outer coils 1 30 of thecondenser. The pipe 29 extends to the inlet pipe 14 to the compressor ata point below the check valve 16.

The valve-casing includes a cup 31 having screw, threaded engagementwith the head 26. Within the cavity of the cup is mounted a largebellows 32 at its bottom in open communication with a thermostatic tube33, the bottom resting on the floor of the cup 31. The upper end of thebellows is soldered to a head 34 having a de- 119 pressed centralportion 35. This depressed portion contains a coil spring 36 engagingagainst a disc 3'7 soldered to the valve stem 38. The head 39 of thevalve cooperates with the valve seat 2'1. A small bellows 40 seals thevalve stem from the outside atmosphere, the inside of the bellows 40being open through the passage 41 to the pressure in the pipes 28, 29.By the selection of a certain refrigerating gas,'the thermostaticelement may be eliminated as the vehicle for temperature control.In'that case, a tube corresponding to the thermostatic tube illustratedherein, will merely be connected to the low side, and the pressure ofthe gas in the low side may be used to act on the by-pass bellows, toeffect the opening and closing thereof in the same manner as describedherein concerning the static operation.

The operation is as follows:

In normal operation, when the temperature of the evaporator is reducedto a predetermined point, the thermostatic liquid in the tube 33 willalso be lowered in temperature, thus reducing the pressure withinthe.bellows 32. The high pressure acting on top of the valve head 39will now be sufllcient to overcome the resistance offered by the bellows32 and the valve head 39 will open slightly. Immediately the highpressure effective in the condenser will enter the space past the valvethrough the passage 41 and into the bellows 40. This will result in aninstantcomplete opening of the valve 39. With the valve 39 open, the gasdischarged from the compressor will be delivered intotwo of the coils ofthe condenser, thence through the pipe 28 past the by-pass 39, into thepipe 29, thence into the intake pipe 14 back to the compressor. Due tothe check valve 16 no pressure is permitted to enter the upper part ofthe pipe 14 or the evaporator. If the level of liquid in the evaporatoris lowered at such periods, the condensed liquid remaining in thecondenser will be delivered into the evaporator in the usual manner, asthe pressure in the condenser is not materially lowered by action of theby-pass valve. Furthermore, the use of a part of the condenser forcirculation of the moving by-passed gas results in a degree of coolingthat will serve to keep down the temperature of the compressor duringidle operation. By utilizing the upper sections of the condenser forthis circulation, I avoid the possibility of withdrawing liquid into thecompressor during idle operation. f

When the temperature raises in the evaporator, the described operationwill be reversed and the valve 39 closes. Normal operation will thenproceed as before. Inasmuch as the valve 39 will be closed slowly, themotor will be reloaded gradually and there will be no sudden pronouncedincrease in the power consumption.

.The form of the thermostatic control is unimportant, the illustrationbeing in a sense diagrammatic. Neither have I illustrated any means formanual adjustment of the temperature conditions, this being anunimportant detail. I may also see fit to suitably insulate thethermostatic tube where it is in the motor compressor area.

It will be understood also that the form of the by-pass valve is notimportant, so far as the broad idea is concerned, the thought conveyedby this disclosure being that of suitable means for unloading andreloading the motor-compressor, the motor being continuously operated.

These and other details herein disclosed may be evaporator, andthermostatically thermovaried within wide limits without departure fromthe spirit of my invention.

I claim:

1. In refrigerating apparatus, the combination of a constantly runningmotor, a compressor, a condenser and an evaporator, and means controlledby the temperature condition of the evaporator for unloading andreloading the motor whereby to maintain a uniform temperature.

2. In refrigerating apparatus, the combination of a compressor, acontinuously running motor for actuating the same, a condenser and ancontrolled means for interrupting compression of gas by the compressorwhen the evaporator has a predetermined temperature.

3. In refrigerating apparatus, the combination of a compressor, acontinuously running motor for actuating the same, a condenser and anevaporator, and thermostatically controlled means for unloading andreloading the motor according to the temperature of the evaporator.

4. In refrigerating apparatus, the combination of a compressor, acontinuously running motor for actuating the same, a condenser and anevaporator, and thermostatically controlled means for by-passing thegasdischarged from the compressor into the intake of the compressor at apressure above the pressure in the evaporator when, the evaporatorreaches a predetermined temperature.

5. In refrigerating apparatus, the combination of an evaporator, acontinuously, running motor, a compressor, a condenser having surfacesat diiferent vertical elevations, a thermostatically controlled valve,and pipes, the passage of gas through whichis controlled by said valve,for bypassing gas fronr the compressor outlet through an upper portionof said condenser and then to the compressor inlet.

6. In refrigerating apparatus, the combination of an evaporator, acontinuously running motor, a compressor having condensing surfaces atdifferent vertical elevations, a thermostatically controlled valve, andpipesthe passage of gas through which is controlled by said valve, forbypassing gaTs from the compressor outlet through an upper portion ofsaid condenser and then to the compressor inlet, and means formaintaining normal high pressure conditions in said condenser duringsaid by-passing operation.

I. In refrigerating apparatus, the combination of a compressor, acontinuously running motor for actuating the same, a condenser and anevaporator, and thermostatically controlled means for unloading andreloading the motor according to the temperature of the evaporator, andmeans for maintaining normal pressure conditions in the condenser duringby-passing operation.

8. In refrigerating apparatus, the combination of a compressor, acontinuously running motor for actuating the same, a condenser and anevaporator, a by-pass valve for unloading and reloading said motor, athermostat for operating said valve, said thermostat being responsive toevaporator temperature and operating to gradually operate the valve toprovide for gradual reloading of the motor.

9. In refrigerating apparatus, the combination of a compressor, acontinuously running motor for-actuating the same, a condenser and anevaporator, and thermostatically controlled means for unloading andgradually reloading the of compressing and non-compressing operation,

an evaporator and a condenser, a portion oi. said system being a highpressure side and a portion of said system being a low pressure side,means for subjecting the piston of said compressor to only one of saidpressure sides during a portion of the operating cycle including aplurality of piston strokes and a check valve on the low pressure sideof said system for preventing high pressure from saidhigh pressure sidefrom entering the evaporator during said portion of the cycle.

RASMUS M. HVlD.

